Highly reliable and reflective LED substrate转让专利
申请号 : US15062001
文献号 : US10559731B1
文献日 : 2020-02-11
发明人 : Phil Elizondo , Joseph Leigh , Brian Cumpston
申请人 : BRIDGELUX, INC.
摘要 :
权利要求 :
What is claimed is:
说明书 :
This application claims the benefit of U.S. Provisional Application Ser. No. 62/128,473, entitled “Highly reliable and reflective LED substrate” and filed on Mar. 4, 2015, which is expressly incorporated by reference herein in its entirety.
The present invention generally relates to reflective substrates and more particularly to light emitting diodes (LED) mounted on reflective substrates that are reliable (or, that exhibit stable properties over time).
Reflective substrates based on physical vapor deposition (PVD) silver (Ag) have become the norm in the LED lighting industry for chip-on-board (COB) arrays and other products. Yet the materials used for these substrates remain plagued by reliability issues. The deposited Ag layer, which is the basis for the highly reflective property, migrates into adjacent layers of the substrate during operation of the LED product. This results in a degradation of the highly reflective property, and subsequent degradation of light output of the LED product. This migration is accelerated by factors such as temperature and exposure to blue light, both of which are prevalent in LED products. Attack of the Ag material by atmospheric sulfur also leads to loss of reflectivity via corrosion of this layer (formation of silver sulfide, also known as tarnish). The loss and/or degradation of reflectivity negatively impact the performance of the LED. product.
Therefore, what is needed is a highly reflective material and/or substrate structure for use in an LED that is stable and will not lose reflectivity as a function of time and operating conditions.
Accordingly, embodiments are directed to techniques and systems that may be used to provide a highly reflective material and/or substrate structure for use in an LED that is stable and will not lose reflectivity as a function of time and/or operating conditions.
Embodiments include a thin film stack that provides adequate protection of the reflective silver (Ag) layer in a substrate used for light emitting diodes (LED) chip-on-board (COB) array products while still providing sufficient reflectivity for lighting applications.
Embodiments include a reflective base for mounting light emitting diodes (LED) including a substrate, an anodic layer disposed over the substrate, an adhesion layer and a barrier layer disposed over the anodic layer, a reflective layer disposed over the adhesion layer and the barrier layer, a first dielectric layer disposed over the reflective layer, and a second dielectric layer disposed over the first dielectric layer. “Anodic” refers more to the process for depositing an aluminum oxide layer, not the material itself. It is incorrect to refer to the AlOx layer above the reflective layer as “anodic.” The anodic process is not feasible for depositing this film; rather it is deposited by PVD techniques such as sputtering or evaporation. The substrate may be made of aluminum or may include aluminum. The substrate may also be made of a flexible material. The anodic layer may include aluminum oxide (AlOx) or may be made of AlOx and may have a thickness of less than 70 nm. In other embodiments, the anodic layer may have a thickness less than 100 nm to help prevent scratching during later processing of the substrate (such as during the dielectric adhesion process, which occurs prior to the die attach process). The anodic layer may be disposed directly over the substrate. The adhesion layer may be disposed directly over the anodic layer. The barrier layer may be disposed directly over the adhesion layer. (FIB analysis show a range of 70-100 nm thickness with the thinner range of 70-100 nm having less total Ag migration compared to the ˜800 nm). The anodic layer may be disposed directly over the substrate. An adhesion layer may be disposed directly over the anodic layer. A barrier layer may be disposed directly over or under the adhesion layer. A single layer may serve both as the adhesion layer and the barrier layer. The reflective layer may be made of silver (Ag) or may include Ag and may have a thickness ranging from 130 nm to 170 nm. In one embodiment, the Ag reflective layer is approximately 150 nm thick. The reflective layer may alternatively be made of pure Ag or alternatively Ag alloyed with platinum (Pt), pallidum (Pd), and/or germanium (Ge). The reflective layer may be disposed directly over the barrier layer. The A first dielectric layer may be disposed directly over the reflective layer. The first dielectric layer may include AlOx or may be made of AlOx and may have a thickness ranging from 40 nm to 80 nm. Other oxide materials may also be used for the first dielectric layer. In one embodiment, the first dielectric AlOx layer is approximately 60 nm thick. The second dielectric layer may be disposed directly over the dielectric layer. A second dielectric layer may include TiOx or may be made of TiOx and may have a thickness ranging from 45 nm to 65 nm. In one embodiment, the TiOx layer is approximately 55 nm thick. The second dielectric layer may be disposed directly over the first dielectric layer. Other oxide materials may also be used for the second dielectric layer.
In other embodiments, the reflective base for mounting light emitting diodes (LED) may further include a third dielectric layer disposed over the second dielectric layer. The third dielectric layer may be made of SiOx or may include SiOx and may have a thickness ranging from 45 nm to 65 nm. In one embodiment, the SiOx layer is approximately 55 nm thick. The third dielectric layer may be disposed directly over the second dielectric layer.
Alternative embodiments include a reflective base for mounting light emitting diodes (LED) including a substrate, an anodic layer disposed over the substrate, a first adhesion layer and a first barrier layer disposed over the anodic layer, a reflective layer disposed over the first adhesion layer and the first barrier layer, a second adhesion layer and a second barrier layer disposed over the reflective layer, a first dielectric layer disposed over the second adhesion layer and the second barrier layer, and a second dielectric layer disposed over the first dielectric layer. The substrate may be made of aluminum or may include aluminum. The substrate may also be made of a flexible material. The anodic layer may include aluminum oxide (AlOx) or may be made of AlOx and may have a thickness of less than 70 nm. In other embodiments, the anodic layer may have a thickness less than 100 nm to help prevent scratching during later processing of the substrate (such as during the dielectric adhesion process, which occurs prior to the die attach process). The anodic layer may be disposed directly over the substrate. The first adhesion layer may be disposed directly over the anodic layer. The (FIB analysis show a range of 70-100 nm thickness with the thinner layer having less total Ag migration). The anodic layer may be disposed directly over the substrate. The first adhesion layer may be disposed directly over the anodic layer. The first barrier layer may be disposed directly over or under the first adhesion layer. In some embodiments a single layer may serve both as the first adhesion layer and the first barrier layer may be disposed directly over the first adhesion layer. The reflective layer may be made of silver (Ag) or may include Ag and may have a thickness ranging from 130 nm to 170 nm. In one embodiment, the Ag reflective layer is approximately 150 nm thick. The reflective layer may be disposed directly over the first barrier layer. The reflective layer may alternatively be made of pure Ag or alternatively Ag alloyed with platinum (Pt), pallidum (Pd), and/or germanium (Ge). The second adhesion layer may be disposed directly over the reflective layer and the second barrier layer may be disposed directly over or under the second adhesion layer. In some embodiments a single layer may serve both as the second adhesion layer and the second barrier layer. The first dielectric layer may be disposed directly over the second barrier layer. The first dielectric layer may include AlOx or may be made of AlOx and may have a thickness ranging from 40 nm to 80 nm. Other oxide materials may also be used for the first dielectric layer. In one embodiment, the first dielectric AlOx layer is approximately 60 nm thick. The second dielectric layer may include TiOx or may be made of TiOx and may have a thickness ranging from 45 nm to 65 nm. In one embodiment, the TiOx layer is approximately 55 nm thick. The second dielectric layer may be disposed directly over the first dielectric layer. Other oxide materials may also be used for the second dielectric layer. The thickness of the oxide layers is designed to protect the reflective layer without impact to reflective layer performance.
In other alternative embodiments, the reflective base for mounting light emitting diodes (LED) may further include a third dielectric layer disposed over the second dielectric layer. The third dielectric layer may be made of SiOx or may include SiOx and may have a thickness ranging from 45 nm to 65 nm. In one embodiment, the SiOx layer is approximately 55 nm thick. The third dielectric layer may be disposed directly over the second dielectric layer.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
Various aspects of the invention will be described herein with reference to drawings that are schematic illustrations of idealized configurations of the present invention. As such, variations from the shapes of the illustrations resulting from manufacturing techniques, tolerances, etc., are to be expected. Thus, the various aspects of the invention presented throughout this disclosure should not be construed as limited to the particular shapes of elements (e.g., regions, layers, sections, substrates, etc.) illustrated and described herein, but are to include deviations in shapes that result, for example, from manufacturing. By way of example, an element illustrated or described as a rectangle may have rounded or curved features and/or a gradient concentration at its edges rather than a discrete change from one element to another.
Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element's relationship to another element as illustrated in the drawings. It will be understood that relative terms are intended to encompass different orientations of an apparatus in addition to the orientation depicted in the drawings. By way of example, if an apparatus in the drawings is turned over, elements disclosed as being on the “lower” side of other elements would then be oriented on the “upper” side of the other elements. The term “lower” may therefore encompass both an orientation of “lower” and “upper,” depending on the particular orientation of the apparatus. Similarly, if an apparatus in the drawing is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The terms “below” or “beneath” may therefore encompass both an orientation of above and below.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and this disclosure.
As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprise,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The term “and/or” includes any and all combinations of one or more of the associated listed items.
Various disclosed aspects may be illustrated with reference to one or more exemplary configurations. As used herein, the term “exemplary” means “serving as an example, instance, or illustration,” and should not necessarily be construed as preferred or advantageous over other configurations disclosed herein.
Furthermore, various descriptive terms used herein, such as “on” and “transparent,” should be given the broadest meaning possible within the context of the present disclosure. It will be understood that when an element such as a region, layer, section, substrate, or the like, is referred to as being “on” another element, it may be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. In addition, something that is described as being “transparent” should be understood as having a property that allows no significant obstruction or absorption of electromagnetic radiation in the particular wavelength (or wavelengths) of interest, unless a particular transmittance is provided. It will be further understood that when an element is referred to as being “formed” on another element, it may be grown, deposited, etched, attached, connected, coupled, or otherwise prepared or fabricated on the other element or an intervening element.
Embodiments include a reflective base for mounting light emitting diodes (LED) including a substrate, an anodic layer disposed over the substrate, an adhesion layer and a barrier layer disposed over the anodic layer, a reflective layer disposed over the adhesion layer and the barrier layer, a first dielectric layer disposed over the reflective layer, and a second dielectric layer disposed over the first dielectric layer. The substrate may be made of aluminum or may include aluminum. The substrate may also be made of a flexible material. The anodic layer may include aluminum oxide (AlOx) or may be made of AlOx and may have a thickness of less than 70 nm. In other embodiments, the anodic layer may have a thickness less than 100 nm to help prevent scratching during later processing of the substrate (such as during the dielectric adhesion process, which occurs prior to the die attach process). The anodic layer may be disposed directly over the substrate. The adhesion layer may be disposed directly over the anodic layer. The barrier layer may be disposed directly over the adhesion layer. The reflective layer may be made of silver (Ag) or may include Ag and may have a thickness ranging from 130 nm to 170 nm. In one embodiment, the Ag reflective layer is approximately 150 nm thick. The reflective layer may alternatively be made of pure Ag or alternatively Ag alloyed with platinum (Pt), pallidum (Pd), and/or germanium (Ge). The reflective layer may be disposed directly over the barrier layer. The first dielectric layer may be disposed directly over the reflective layer. The first dielectric layer may include AlOx or may be made of AlOx and may have a thickness ranging from 40 nm to 80 nm. Other oxide materials may also be used for the first dielectric layer. In one embodiment, the first dielectric AlOx layer is approximately 60 nm thick. The second dielectric layer may include TiOx or may be made of TiOx and may have a thickness ranging from 45 nm to 65 nm. In one embodiment, the TiOx layer is approximately 55 nm thick. The second dielectric layer may be disposed directly over the first dielectric layer. Other oxide materials may also be used for the second dielectric layer.
In other embodiments, the reflective base for mounting light emitting diodes (LED) may further include a third dielectric layer disposed over the second dielectric layer. The third dielectric layer may be made of SiOx or may include SiOx and may have a thickness ranging from 45 nm to 65 nm. In one embodiment, the SiOx layer is approximately 55 nm thick. The third dielectric layer may be disposed directly over the second dielectric layer.
Alternative embodiments include a reflective base for mounting light emitting diodes (LED) including a substrate, an anodic layer disposed over the substrate, a first adhesion layer and a first barrier layer disposed over the anodic layer, a reflective layer disposed over the first adhesion layer and the first barrier layer, a second adhesion layer and a second barrier layer disposed over the reflective layer, a first dielectric layer disposed over the second adhesion layer and the second barrier layer, and a second dielectric layer disposed over the first dielectric layer. The substrate may be made of aluminum or may include aluminum. The substrate may also be made of a flexible material. The anodic layer may include aluminum oxide (AlOx) or may be made of AlOx and may have a thickness of less than 70 nm. In other embodiments, the anodic layer may have a thickness less than 100 nm to help prevent scratching during later processing of the substrate (such as during the dielectric adhesion process, which occurs prior to the die attach process). The anodic layer may be disposed directly over the substrate. The first adhesion layer may be disposed directly over the anodic layer. The first barrier layer may be disposed directly over the first adhesion layer. The reflective layer may be made of silver (Ag) or may include Ag and may have a thickness ranging from 130 nm to 170 nm. In one embodiment, the Ag reflective layer is approximately 150 nm thick. The reflective layer may be disposed directly over the first barrier layer. The reflective layer may alternatively be made of pure Ag or alternatively Ag alloyed with platinum (Pt), pallidum (Pd), and/or germanium (Ge). The second adhesion layer may be disposed directly over the reflective layer and the second barrier layer may be disposed directly over the second adhesion layer. The first dielectric layer may be disposed directly over the second barrier layer. The first dielectric layer may include AlOx or may be made of AlOx and may have a thickness ranging from 40 nm to 80 nm. Other oxide materials may also be used for the first dielectric layer. In one embodiment, the first dielectric AlOx layer is approximately 60 nm thick. The second dielectric layer may include TiOx or may be made of TiOx and may have a thickness ranging from 45 nm to 65 nm. In one embodiment, the TiOx layer is approximately 55 nm thick. The second dielectric layer may be disposed directly over the first dielectric layer. Other oxide materials may also be used for the second dielectric layer.
In other alternative embodiments, the reflective base for mounting light emitting diodes (LED) may further include a third dielectric layer disposed over the second dielectric layer. The third dielectric layer may be made of SiOx or may include SiOx and may have a thickness ranging from 45 nm to 65 nm. In one embodiment, the SiOx layer is approximately 55 nm thick. The third dielectric layer may be disposed directly over the second dielectric layer.
In some embodiments, the substrate 210 may be made of aluminum or may include aluminum as well as other materials. The substrate 210 may also be made of a flexible material. The anodic layer 212 may include aluminum oxide (AlOx) or may be made of AlOx and other materials. In other embodiments, the anodic layer 212 may have a thickness less than 100 nm to help prevent scratching during later processing of the substrate (such as during the dielectric adhesion process, which occurs prior to the die attach process). The reflective layer 218 may be made of silver (Ag) or may include Ag as well as other materials and may have a thickness ranging from 130 nm to 170 nm. The reflective layer 218 may alternatively be made of pure Ag or alternatively Ag alloyed with platinum (Pt), pallidum (Pd), and/or germanium (Ge). The first dielectric layer 220 may include AlOx or may be made of AlOx as well as other materials and may have a thickness ranging from 40 nm to 80 nm. Other oxide materials may also be used for the first dielectric layer 220. The second dielectric layer 222 may include TiOx or may be made of TiOx as well as other materials and may have a thickness ranging from 45 nm to 65 nm. Other oxide materials may also be used for the second dielectric layer 222.
In some embodiments, the adhesion layer 214 may include metals such as chromium, nickel, titanium and/or other materials so long as it assists with adhesion of the adjacent layers together. The adhesion layer 214 may have a thickness ranging from 1 to 10 nm. In some embodiments, the barrier layer 216 may be metallic, dielectric or transparent so long as it reduces or prevents the migration of Ag and/or reduces or prevents the migration of sulfur into the reflective Ag layer 218. The barrier layer 216 may have a thickness ranging from 1 to 10 nm.
A comparison of the reflective bases illustrated in
In some embodiments, the substrate 310 may be made of aluminum or may include aluminum as well as other materials. The substrate 310 may also be made of a flexible material. The anodic layer 312 may include aluminum oxide (AlOx) or may be made of AlOx and other materials. In other embodiments, the anodic layer 312 may have a thickness less than 100 nm to help prevent scratching during later processing of the substrate (such as during the dielectric adhesion process, which occurs prior to the die attach process). The reflective layer 318 may be made of silver (Ag) or may include Ag as well as other materials and may have a thickness ranging from 130 nm to 170 nm. The reflective layer 318 may alternatively be made of pure Ag or alternatively Ag alloyed with platinum (Pt), pallidum (Pd), and/or germanium (Ge). The first dielectric layer 324 may include AlOx or may be made of AlOx as well as other materials and may have a thickness ranging from 40 nm to 80 nm. Other oxide materials may also be used for the first dielectric layer 324. The second dielectric layer 326 may have a thickness ranging from 45 nm to 65 nm. Other oxide materials may also be used for the second dielectric layer 326.
In some embodiments, the first adhesion layer 314 may include metals such as chromium, nickel, titanium and/or other materials so long as it assists with adhesion of the adjacent layers together. The first adhesion layer 314 may have a thickness ranging from 1 to 10 nm. In some embodiments, the first barrier layer 316 may be metallic, dielectric or transparent so long as it reduces or prevents the migration of Ag and/or reduces or prevents the migration of sulfur into the reflective Ag layer 318. The first barrier layer 316 may have a thickness ranging from 1 to 10 nm. The second adhesion layer 320 may also include metals such as chromium, nickel, titanium and/or other materials so long as it assists with adhesion of the adjacent layers together. The second adhesion layer 320 may have a thickness ranging from 1 to 10 nm. In some embodiments, the second barrier layer 322 may be metallic, dielectric or transparent so long as it reduces or prevents the migration of Ag and/or reduces or prevents the migration of sulfur into the reflective Ag layer 318. The second barrier layer 322 may have a thickness ranging from 1 to 10 nm.
A comparison of the reflective bases illustrated in
In some embodiments, the substrate 410 may be made of aluminum or may include aluminum as well as other materials. The substrate 410 may also be made of a flexible material. The anodic layer 412 may include aluminum oxide (AlOx) or may be made of AlOx and other materials. In other embodiments, the anodic layer 412 may have a thickness less than 100 nm to help prevent scratching during later processing of the substrate (such as during the dielectric adhesion process, which occurs prior to the die attach process). The reflective layer 418 may be made of silver (Ag) or may include Ag as well as other materials and may have a thickness ranging from 130 nm to 170 nm. The reflective layer 418 may alternatively be made of pure Ag or alternatively Ag alloyed with platinum (Pt), pallidum (Pd), and/or germanium (Ge). The first dielectric layer 420 may include AlOx or may be made of AlOx as well as other materials and may have a thickness ranging from 40 nm to 80 nm. Other oxide materials may also be used for the first dielectric layer 420. The second dielectric layer 422 may have a thickness ranging from 45 nm to 65 nm. Other oxide materials may also be used for the second dielectric layer 422. The third dielectric SiOx layer 424 may have a thickness ranging from 45 nm to 65 nm. Other oxide materials may also be used for the third dielectric layer 424.
In some embodiments, the adhesion layer 414 may include metals such as chromium, nickel, titanium and/or other materials so long as it assists with adhesion of the adjacent layers together. The adhesion layer 414 may have a thickness ranging from 1 to 10 nm. In some embodiments, the barrier layer 416 may be metallic, dielectric or transparent so long as it reduces or prevents the migration of Ag and/or reduces or prevents the migration of sulfur into the reflective Ag layer 418. The barrier layer 416 may have a thickness ranging from 1 to 10 nm.
A comparison of the reflective bases illustrated in
In some embodiments, the substrate 510 may be made of aluminum or may include aluminum as well as other materials. The substrate 510 may also be made of a flexible material. The anodic layer 512 may include aluminum oxide (AlOx) or may be made of AlOx and other materials. In other embodiments, the anodic layer 512 may have a thickness less than 100 nm to help prevent scratching during later processing of the substrate (such as during the dielectric adhesion process, which occurs prior to the die attach process). The reflective layer 518 may be made of silver (Ag) or may include Ag as well as other materials and may have a thickness ranging from 130 nm to 170 nm. The reflective layer 518 may alternatively be made of pure Ag or alternatively Ag alloyed with platinum (Pt), pallidum (Pd), and/or germanium (Ge). The first dielectric layer 524 may include AlOx or may be made of AlOx as well as other materials and may have a thickness ranging from 40 nm to 80 nm. Other oxide materials may also be used for the first dielectric layer 524. The second dielectric layer 526 may have a thickness ranging from 45 nm to 65 nm. Other oxide materials may also be used for the second dielectric layer 526. The third dielectric SiOx layer 528 may have a thickness ranging from 45 nm to 65 nm. Other oxide materials may also be used for the third dielectric layer 528.
In some embodiments, the first adhesion layer 514 may include metals such as chromium, nickel, titanium and/or other materials so long as it assists with adhesion of the adjacent layers together. The first adhesion layer 514 may have a thickness ranging from 1 to 10 nm. In some embodiments, the first barrier layer 516 may be metallic, dielectric or transparent so long as it reduces or prevents the migration of Ag and/or reduces or prevents the migration of sulfur into the reflective Ag layer 518. The first barrier layer 516 may have a thickness ranging from 1 to 10 nm. The second barrier layer 520 may also include metals such as chromium, nickel, titanium and/or other materials so long as it assists with adhesion of the adjacent layers together. The second barrier layer 520 may have a thickness ranging from 1 to 10 nm. In some embodiments, the second adhesion layer 522 may be metallic, dielectric or transparent so long as it reduces or prevents the migration of Ag and/or reduces or prevents the migration of sulfur into the reflective Ag layer 518. The second adhesion layer 522 may have a thickness ranging from 1 to 10 nm.
A comparison of the reflective bases illustrated in
The reliability of LED structures may be improved by reducing the thickness of the anodic Al2O3 layer by roughly one order of magnitude. This greatly limits the amount of Ag that may migrate into this layer. In some embodiments, described with reference to
In embodiments, the substrate (110, 210, 310, 410, 510) and the anodic layer (112, 212, 312, 412, 512), either individually or in combination, have substantially smooth surfaces to allow subsequent layers to cover and protect the reflective layer. Further, the upper dielectric layers, which include the first dielectric layer 120, 220, 324, 420 and 524, the second dielectric layer 122, 222, 326, 422, and 525, and the third dielectric layer 424 and 528, are substantially homogenous and substantially free of cracks and pin holes. In some situations, if the upper dielectric layers are not homogeneous due to cracks or pin holes, then the Ag will migrate upwards and cause the reflective layer to degrade.
In addition, certain LEDs may work well with the reflective base 100, 200, 300, 400, 500. For example, DBR structures implements multiple layers with varying refractive indices to reflect and guide the emitted light. As such, the DBR structure may focus the emitted light more intensely and exacerbate the migration of the reflective material. Providing LED devices that have DBR structures with the reflective base 100, 200, 300, 400, 500 may tend reduce migration of the reflective material. In an embodiment, an LED device may have a distributed Bragg reflector (DBR) structure and the reflective base 100, 200, 300, 400, 500. Likewise, an omni-directional reflectors (ODR) structure has a reflective surface on the LED that directs the emitted-light. Like, DBR structures, ODR may tend to exacerbate the migration of the reflective material. Providing LED devices that have ODR structures with the base reflect 100, 200, 300, 400, 500 may tend reduce migration of the reflective material. In another aspect, an LED device may have an omni-directional reflector (ODR) structure with the LED and the reflective base 100, 200, 300, 400, 500.
The inventions and methods described herein may be viewed as a whole, or as a number of separate inventions that may be used independently or mixed and matched as desired. All inventions, steps, processes, devices, and methods described herein may be mixed and matched as desired. All previously described features, functions, or inventions described herein or by reference may be mixed and matched as desired.
It will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.